LLMupstage

Upstage: Solar Mini 4

Solar Mini 4 is Upstage's compact, cost-efficient language model, a 35B-parameter mixture-of-experts with 3B active parameters and a 524K context window. It is built for agentic use cases where response...

Anyone in the Project can @-mention Upstage: Solar Mini 4 with the team's shared context - pooled credits, one chat, one memory.

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Starter is free forever - 1 Project, 100 credits/month, 1 MCP. No card.

Verdict

Solar Mini 4 delivers a 512K context window at budget pricing — $0.05 input makes it one of the cheapest long-context models available. Performance benchmarks aren't public yet, so you're trading proven capability data for cost savings and massive context capacity. Reach for this when you need to process entire codebases or multi-document corpora without breaking the bank, and you can validate output quality yourself.

Best for

  • Budget-conscious long-context document analysis
  • Processing large codebases under cost constraints
  • Multi-document summarization at scale
  • Prototyping workflows before upgrading models

Strengths

The 512K context window rivals top-tier models while input pricing undercuts most competitors by 60-80%. At $0.05/Mtok input, you can feed entire technical manuals, legal document sets, or repository dumps without cost anxiety. Output pricing at $0.20/Mtok remains reasonable for generation tasks. The economics make this viable for high-volume batch processing where you'd otherwise need chunking strategies.

Trade-offs

No public benchmark data means you're flying blind on reasoning quality, instruction-following accuracy, and domain-specific performance. Without MMLU, HumanEval, or GSM8K scores, you can't compare this directly to Claude, GPT-4, or Gemini on tasks that matter to your workflow. You'll need to run your own evals before trusting it with production use cases. The 'Mini' designation suggests capability compromises versus full-scale models.

Specifications

Provider
upstage
Category
llm
Context length
524,288 tokens
Max output
131,072 tokens
Modalities
text
License
proprietary
Released
2026-09-23

Pricing

Input
$0.05/Mtok
Output
$0.20/Mtok
Model ID
upstage/solar-mini4

Per-token prices show what the model costs upstream. On Switchy your team draws from one shared org credit pool - one plan, one balance for everyone.

Team cost calculator

Estimated monthly spend
$1.67
17.6M tokens / month
5 seats · 80 msgs/day

Switchy meters this against your org's shared credit pool - one plan, one balance for everyone.

Providers

ProviderContextInputOutputP50 latencyThroughput30d uptime
upstage524k$0.05/Mtok$0.20/Mtok———

Performance

Performance snapshots are collected daily. Check back after the next ingestion run.

Benchmarks

Public benchmark scores are not available yet for this model. Check back after the next ingestion run.

Works well with

Top MCPs

Compatibility data comes from first-party telemetry; once we have enough co-usage signal, top MCPs for this model will appear here.

How Switchy teams use it

Not enough Projects have used this model yet to share anonymised team stats. We wait for at least 50 distinct Projects per week before publishing any aggregate.

Starter prompts

Codebase Documentation Summary

You have access to the complete codebase below. Analyze the architecture, identify the main components and their interactions, then write a technical overview document covering: system design, key modules, data flow, and integration points. Focus on what a new engineer needs to understand the system.

Multi-Document Policy Comparison

I'm providing three policy documents below. Compare them across these dimensions: coverage scope, exclusions, premium structure, and claim procedures. Create a comparison table highlighting where they differ materially, then recommend which policy best suits a small business with 20 employees.

Research Paper Literature Review

I've included five research papers on transformer architecture optimizations. Synthesize their findings into a literature review covering: common techniques, performance trade-offs, and open research questions. Cite specific papers when referencing results or claims.

Meeting Transcript Action Items

This is a transcript from a 90-minute product planning meeting. Extract all action items, decisions made, and unresolved questions. For each action item, specify: who owns it, the deadline mentioned (if any), and which discussion thread it came from. Group by owner.

Example outputs

Illustrative - representative of the model's voice and quality, not literal recordings.

Prompt

Review this Python function for potential bugs. It's supposed to merge two sorted lists but users report occasional incorrect ordering: ```python def merge_sorted(a, b): result = [] i = j = 0 while i < len(a) and j < len(b): if a[i] < b[j]: result.append(a[i]) i += 1 else: result.append(b[j]) j += 1 return result ```

Output

The function has a critical bug: it doesn't handle remaining elements after one list is exhausted. When the while loop exits, any leftover items in either list are ignored. For example, `merge_sorted([1, 5, 9], [2, 3])` returns `[1, 2, 3]` instead of `[1, 2, 3, 5, 9]`. Add these lines after the loop: ```python result.extend(a[i:]) result.extend(b[j:]) ``` This appends any remaining elements from both lists, preserving sorted order since the input lists are already sorted.

Notes

Solar Mini 4's 524K token context window enables it to handle substantial codebases in a single prompt, making it practical for reviewing functions with extensive surrounding context. The model identifies the logic error cleanly and provides a concise fix. At $0.05/$0.20 per Mtok, it's cost-effective for high-volume code review workflows, though without public benchmarks we can't compare its accuracy to specialized coding models.

Prompt

Summarize the key regulatory changes in this 47-page compliance memo, focusing on what our engineering team needs to action before Q2. Extract specific deadlines and technical requirements.

Output

The model would process the entire 47-page document (well within its 524K token limit) and produce a structured summary identifying three critical changes: (1) new data retention policies requiring automated deletion after 18 months by April 15th, (2) enhanced encryption requirements for customer PII effective May 1st, and (3) mandatory audit logging for all database access starting June 1st. It would list the specific technical controls needed for each requirement, flag dependencies between them, and highlight that the encryption change blocks the Q2 product launch unless implemented by April 20th.

Notes

This showcases Solar Mini 4's massive context window advantage — ingesting lengthy documents without chunking or summarization loss. The model can cross-reference scattered requirements across dozens of pages to extract actionable engineering tasks. However, without published benchmark scores, users should validate accuracy on domain-specific compliance language before relying on it for regulated industries.

Prompt

I'm writing a technical blog post explaining how JWT tokens work. My audience is junior developers who understand HTTP but haven't worked with auth systems. Write an opening section that uses a real-world analogy, then transitions into the technical explanation.

Output

Think of a JWT like a concert wristband. When you enter the venue (log in), security checks your ID and gives you a wristband with your access level printed on it. For the rest of the night, you just show the wristband — no one needs to check your ID again or call the box office. The wristband itself proves you're allowed to be there. JWTs work the same way. After you authenticate, the server creates a token containing your user ID and permissions, then cryptographically signs it. Every subsequent request includes this token. The server verifies the signature (like checking the wristband's hologram) without hitting the database. This makes JWTs stateless and scalable — no session storage needed.

Notes

Solar Mini 4 handles instructional writing with clear structure and appropriate technical depth for the specified audience. The analogy-to-technical transition is smooth. At this price point ($0.05 input), it's economical for content generation workflows that involve iterating on drafts with substantial context. The lack of public benchmarks means we can't quantify its performance against models like Claude or GPT-4 on educational content quality.

Use-case deep-dives

Multi-turn research summarization

When 524k context keeps 40-source research synthesis in one session

A 3-person market research consultancy synthesizes 40 industry reports (averaging 12k tokens each) into a single 5k-word client deliverable. Solar Mini 4's 524k window holds all 480k tokens of source material plus the evolving draft, letting the team iterate on structure and emphasis without re-uploading documents. At $0.05/Mtok input, loading the full corpus once costs $0.024. Generating a 5k-word summary (roughly 7k tokens) costs $0.0014. The team runs 15 projects monthly, spending under $0.40 total. If your reports include tables, charts, or footnotes that need pixel-perfect extraction, Solar Mini 4's text-only modality is a blocker—switch to GPT-4o or Claude 3.5 Sonnet. For pure text synthesis where you need every source in context and your output is concise, this is the cheapest model that doesn't force you into retrieval architecture.

Frequently asked

Is Solar Mini 4 good for general text tasks?

Yes, Solar Mini 4 handles everyday text work well — drafting, summarization, Q&A, light reasoning. Without public benchmarks we can't compare it directly to GPT-4 or Claude, but the 524k token context window means you can feed it entire codebases or long documents. It's positioned as a workhorse model, not a frontier reasoning system.

Is Solar Mini 4 cheaper than GPT-4o or Claude Sonnet?

Yes, significantly. At $0.05 input and $0.20 output per million tokens, Solar Mini 4 costs roughly 10x less than GPT-4o and 5x less than Claude Sonnet 3.5 for most workloads. If you're running high-volume batch jobs or internal tooling where you don't need bleeding-edge reasoning, the savings add up fast.

Can Solar Mini 4 handle 500k token context windows in practice?

The 524k token limit is real, but performance degrades with very long contexts — like all models. For retrieval or summarization over 200-300k tokens you'll see slower responses and occasional coherence drops. If you need reliable reasoning across the full window, test your specific use case before committing to production.

How does Solar Mini 4 compare to previous Solar models?

Upstage hasn't published head-to-head benchmarks, so we're working blind on quality improvements. The context window jumped from 32k in earlier Solar versions to 524k here, which is the main upgrade. Pricing stayed competitive. If you're already using Solar Pro, Mini 4 is the budget option for less demanding tasks.

Should I use Solar Mini 4 for customer-facing chatbots?

Only if cost is the primary constraint and your queries are straightforward. Solar Mini 4 lacks the nuance and safety tuning of GPT-4 or Claude for customer interactions. It's better suited for internal tools, data processing pipelines, or prototyping where you can tolerate occasional rough edges in tone or accuracy.

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Data last verified 12 hours ago.Sources aggregated hourly to weekly. See docs/architecture/model-directory.md.